Cholesterol is a polycyclic steroidal alcohol found in all body tissues, especially in animal meats, fats and oils. For nutritional and human health purposes, cholesterol is typically measured by determining its concentration in the serum or plasma, in which the normal range concentration is usually given as between 140-240 mg/dl. About three-fourths of the serum cholesterol is esterified with unsaturated long-chain fatty acids; the remainder of the serum cholesterol is present in the free cholesterol form.
For medical and diagnostic purposes, serum cholesterol is associated with the high-density lipoprotein (HDL) and low-density lipoprotein (LDL) fractions in a ratio of about 1:3. High-serum total cholesterol, and/or LDL cholesterol, and low HDL cholesterol concentrations are considered high risk factors for arteriosclerosis, the major cause of death in the United States characterized by focal fatty thickening in the inner aspects of large arterial vessels supplying blood to the heart, brain, and other vital organs. For more than a century scientists have associated these atherosclerotic lesions with the accumulation of lipids, specifically cholesterol and its esters, upon the inner layers (intima) of large arteries [Small, D. M. and G. G. Shipley, Science 185:222-229 (1974); D. M. Small, The Lymen Duff Lecture: "Progression and Regression of Atherosclerotic Lesions", given at the 59th Scientific Session of the American Heart Association, Dallas, Texas, November 1986 and published in Arteriosclerosis, Vol. 8, pages 103-129; D. M. Small, "The Physical State Of Lipids Of Biological Importance: Cholesterol Esters, Cholesterol, Triglyceride", Surface Chemistry Of Biological Systems, Plenum Press, 1970 pages 55-83]. This has also lead to considerable research on the solubility and distribution of cholesterol, saturated fats, and other lipids within human and animal tissues and within a variety of different fats and oils. For more detailed information regarding cholesterol solubility and cholesterol in its various crystalline forms, the following reference is recommended, the text of which is expressly incorporated by reference herein: D. M. Small, The Physical Chemistry Of Lipids From Alkanes To Phospholipids, Plenum Press, 1986.
It will be noted and appreciated that the long-term nutritional and health results of eating less cholesterol and less saturated fat in our diets have been discussed and recognized by the American Heart Association and the National 23 Cholesterol Education Program [Arch. Intern. Med. 148:36-69 (1988)]. It is now generally believed that a marked decrease in cardiovascular disease could occur if the dietary intake of saturated fat and cholesterol were seriously reduced in the American population. Cardiovascular disease is still by far the major killer of people in Western society and major steps have been implemented to reduce this epidemic common to those with a high standard of living. In the opinion of the National Cholesterol Education Committee and the American Heart Association, a decreased intake of dietary cholesterol and saturated fat would mediate and have a marked effect in reducing the incidence of cardiovascular disease.
Several approaches have been undertaken to try and reduce the dietary intake of cholesterol and saturated fat by the American public. One approach has been to educate the public regarding nutrition and health risks regarding the kinds of foods containing high cholesterol and high saturated fats; this has resulted in a major shift in the eating habits of the consuming public away from foods such as hard cheese and fatty red meats towards those foods such as fish and fowl containing substantially less cholesterol and saturated fat. Another approach has been to treat or process meats from various animal sources to reduce their fat content. These typically have taken three forms: The removal of fat from meat by mechanical means such as a crusher, a press or cutting tools; physical treatments including heat, light, and reactive gas; and chemical treatments with water or strong chemical reagents. The presently available mechanical apparatus modes of treatment are exemplified by U.S. Pat. Nos. 4,776,063; 3,780,191; 3,748,148; and 3,685,095; Japanese patent publication Nos. 62265396 (871118); 61158763 (860718); French Pat. No. 2,187,229; and British Pat. No. 1179418. The conventionally known heat and other physical treatments of meat are represented by Japanese patent Publication Nos. 62278967 (871203), 61058533 (860325), 59173070 (840929), 59084993 (840516), 58187496 (831101); Soviet Union Publication Nos. 1153874 (850507), 627810 (780821), 502011 (760825), 1318420 (690331); and U.S. Pat. Nos. 4,778,682; 3,687,819; 3,780,075; and 3,532,593. The previously used chemical treatments of meats are illustrated by Soviet Union Publication Nos. 1329737 (870815), 1063824 (831230) 1017684 (830515); German patent Publication Nos. 200156 (830323), 3169440 (850425), 2119608 (710422); Japanese patent Publication Nos. 56018537 (810221), 55156569 (801205), 54003099 (790111), 52040473 (770329); and U.S. Pat. Nos. 3,794,743; and 3,532,593 respectively.
Despite all these innovations, the currently known procedures collectively and cumulatively are and remain ineffective for the purpose of substantially reducing cholesterol and the associated saturated fats from meats and fowl. All of the generally known and available procedures typically involve the grinding or crushing of meat and/or its chemical and physical extraction with hot water, or steam, or heat, or pressure, or some combination of these treatments. The technical problem remaining unappreciated and unresolved to date in the removal of cholesterol and saturated fats relates to their location in the meat obtained from animals. Virtually all of the cholesterol within edible meats exists in the free form and is located in the membranes of the cells within the meat tissue rather than in the meat (muscle) itself. Cholesterol and saturated fats, can of course be analytically extracted and quantitatively measured by grinding meat and using strong organic solvents such as chloroform and methanol; however, neither cholesterol nor saturated fat can be effectively extracted from edible meats and meat products simply by employing heat, water, or steam. Water and steam can be employed to melt some fats, particularly triglycerides, which then can be physically removed in part; nevertheless, these treatments cannot extract the cholesterol or change the saturated fatty acid character of meat, particularly with red meats such as beef, pork and lamb. Accordingly, it will be recognized and appreciated that there remains a long standing, recognized need for improved methods for reducing the cholesterol content and saturated fat content of meats in general. Similarly, the use of such methods to produce meat and meat products with markedly reduced cholesterol and saturated fat would be recognized as a major advance in reducing the dietary intake of saturated fat and cholesterol leading to a marked decrease in cardiovascular disease.